Coming to Europe this summer -- jellyfish

Stinging jellyfish are besieging shorelines across the Mediterranean, threatening the health of tourists.

Sharks. Sea Snakes. Sewage.

Lots of unpleasant things can keep us out of the ocean, ruining an otherwise enjoyable beach holiday.

Perhaps no sea creature makes swimmers quite so paranoid as jellyfish -- “gelatinous macrozooplankton” if you really want to make yourself feel squeamish.

Now European scientists are warning that a surge in the number of jellyfish could threaten not only marine biodiversity, but also the health of tourists in beach resorts around the Mediterranean and Black Sea.

“In the last decade … the media are reporting on an increasingly high number of gelatinous plankton blooms,” reads the report. “The reason for these reports is that thousands of tourists are stung, fisheries are harmed and even impaired by jellyfish.”

Although noting that significant jellyfish blooms “have been known since ancient times and are part of the normal functioning of the oceans,” the report cites global warming and global over-fishing (which removes jellyfish predators) as causes for exploding jellyfish populations in recent years.

“There are now beaches on the [Italian] island of Lampedusa, which receive 300,000 tourists a year, where people can only swim for a week in the summer,” according to Salento University (Italy) professor Stefano Piraino, in an article in the Guardian.

According to the same Guardian article, Barcelona’s Institute of Marine Sciences “has detected a surge this spring in one of the most poisonous species, the mauve stinger or Pelagia noctiluca, along the coast of Catalonia and Valencia.” The coastlines most badly affected by the overall surge in jellyfish populations include Malta, Sardinia, Sicily and areas of Israel and Lebanon, the article says.

According to the General Fisheries Commission for the Mediterranean report, the region’s first case of a lethal sting from a jellyfish occurred in Sardinia in 2010.

“Sea-based tourism is one of the main sources of income in the whole Mediterranean Sea. If stinging jellyfish persist, stung tourists can cancel their reservations or reduce the length of their stay, with a reduction of revenues from tourism,” reads the study.